There is a need in the process industries for a mixing or drying method which is simple and inexpensive, and affords greater throughput by performing mixing or drying in a short amount of time. One type of prior art mixing apparatus is described in U.S. Pat. No. 4,136,972. This apparatus utilizes a plurality of elongated interdigitated rotors and stators with the rotors and stators being twisted with respect to the horizontal in order to provide rotor and stator first portions having predetermined acute angles with respect to rotor and stator second portions. The rotors cooperate with the stators to cause the material desired to be mixed to move in a flow loop down along the walls of an enclosing cylindrical container and up along the rotor shaft. Although the apparatus described in this patent has many advantages over the prior art the material flow pattern that is generated is specifically designed to minimize inclusion of air into the final mixed product and in addition finds application primarily in the mixing of liquid-liquid materials or liquid-solid materials which require complete uniformity of mix without the addition of air in a very short period of time. The search has, therefore, continued for an improved mixing/drying device applicable to other materials.
Accordingly, it is an object of this invention to provide a simple and inexpensive mixing or drying method for particulate materials.
It is a further object of this invention to provide a mixing or drying method which achieves the mixing or drying in a shorter period of time than known arrangements.
It is another object of this invention to provide a mixing or drying method for particulate material which does not require the use of stator blades.
It is a still further object of this invention to provide a mixing or drying method which can be utilized for batch or continuous mixing of any particulate material.